Make some f_Group definitions anonymous and test an alternative spelling

These names weren't referred to anywhere in the source so don't need a written
name.

Depends on the TableGen fix for anonymous records in LLVM r197869.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197896 91177308-0d34-0410-b5e6-96231b3b80d8